Distribution system state estimation faces a major difficulty: the lack of real-time measurements. This imposes to add information, usually pseudo-measurements from historical data. This paper proposes a ... [more ▼]

Distribution system state estimation faces a major difficulty: the lack of real-time measurements. This imposes to add information, usually pseudo-measurements from historical data. This paper proposes a different, novel formulation of state estimation relying on the classification of loads into components (e.g. residential, commercial, etc.) and accounting for dispersed generation. The approach “by-passes” the use of pseudo-measurements by expressing the medium-voltage bus injections as functions of a small number of active power components at low-voltage level, treated as additional state variables. The injections at medium-voltage buses become equality constraints. A procedure to identify the above functions is detailed, which takes advantage of data collected by smart meters. [less ▲]

Synchronized phasor measurement units (PMUs) are becoming a reality in more and more power systems, mainly at the transmission level. This paper presents, in a tutorial manner, the benefits that existing ... [more ▼]

Synchronized phasor measurement units (PMUs) are becoming a reality in more and more power systems, mainly at the transmission level. This paper presents, in a tutorial manner, the benefits that existing and future State Estimators (SE) can achieve by incorporating these devices in the monitoring process. After a review of the relevant PMU technological aspects and the associated deployment issues (observability, optimal location, etc.), the alternative SE formulations in the presence of PMUs are revisited. Then, several application environments are separately addressed, regarding the enhancements potentially brought about by the use of PMUs. [less ▲]

This paper presents a critical review of the state of the art in Multi-Area State Estimation (MASE) methods, which are currently gaining renewed interest due to their capability of properly tracking multi ... [more ▼]

This paper presents a critical review of the state of the art in Multi-Area State Estimation (MASE) methods, which are currently gaining renewed interest due to their capability of properly tracking multi-TSO transactions and accommodating highly redundant information systems. Based on several classification criteria, a taxonomy of MASE methods is first proposed. Two main categories, namely two-step or hierarchical versus decentralized, are identified. Then, for each class of methods, the resulting model structure and area interactions are discussed and a brief presentation is made of a selected subset of references. [less ▲]

This paper presents research and education activities of the power systems group of the Department of Electrical Engineering and Computer Science of the University of Liège. These activities cover power ... [more ▼]

This paper presents research and education activities of the power systems group of the Department of Electrical Engineering and Computer Science of the University of Liège. These activities cover power systems stability, security, reliability, and markets, within the contexts of expansion planning, operation planning and real-time operation and automatic control. The paper also reviews the international collaborations of the team. [less ▲]

This paper deals with the quasi steady-state approximation of the long-term dynamics. This fast time simulation method assumes that the short-term dynamics are stable and can be replaced by their ... [more ▼]

This paper deals with the quasi steady-state approximation of the long-term dynamics. This fast time simulation method assumes that the short-term dynamics are stable and can be replaced by their equilibrium equations. When the latter stop having a solution, the simulation undergoes a singularity. This paper proposes a method to identify which component(s) are responsible for the loss of equilibrium. The corresponding equations are identified using the Newton method with optimal multiplier. The method has been validated with respect to full time simulation. Very good results are shown on the Nordic-32 system, in cases where long-term voltage instability triggers loss of synchronism. The proposed method enhances time simulation at very low computational cost and can also help correcting model and/or operating point errors. [less ▲]

in Proceedings of the 15th Power System Computation Conference (PSCC) (2005)

This paper describes a methodology for the study of long-term network planning under uncertainties. In this approach the major external uncertainties during the planning horizon are modelled as macro ... [more ▼]

This paper describes a methodology for the study of long-term network planning under uncertainties. In this approach the major external uncertainties during the planning horizon are modelled as macro-scenarios at different future time instants. The random nature of actual operating conditions is taken into account by using a probabilistic model of micro-scenarios based on past statistics. MonteCarlo simulations are used to generate and simulate a speciﬁed number of scenarios. Data mining techniques are then applied to the simulations results collected in a database, so as to extract information and to rank scenarios and network reinforcements according to different performance criteria. The paper describes the application of this approach on a real transmission planning problem faced by the Belgian transmission system operator. [less ▲]

This work proposes a methodology and a practical tool for the study of long-term network planning under uncertainties. In this approach the major external uncertainties during the planning horizon are ... [more ▼]

This work proposes a methodology and a practical tool for the study of long-term network planning under uncertainties. In this approach the major external uncertainties during the planning horizon are modeled as macroscenarios at different future time instants. On the other hand, the random nature of actual operating conditions is taken into account by using a probabilistic model of microscenarios based on past statistics. Massive Monte-Carlo simulations are used to generate and simulate a large number of scenarios and store the detailed results in a relational database. Data mining techniques are then applied to extract information from the database so as to rank scenarios and network reinforcements according to different criteria. [less ▲]

in Proceedings of the IEEE Porto Power Tech Conference (2001, September)

This paper proposes a time domain simulation tool combining Full Time Scale (FTS) simulation in the short-term period following a contingency and Quasi Steady-State (QSS) approximation for the long-term ... [more ▼]

This paper proposes a time domain simulation tool combining Full Time Scale (FTS) simulation in the short-term period following a contingency and Quasi Steady-State (QSS) approximation for the long-term phase. A criterion is devised to automatically switch from FTS to QSS simulation as soon as sufficient damping of short-term dynamics is reached. Various comparisons with FTS simulations have been performed on the Hydro-Qn6bec system. The proposed method is shown to combine accuracy of FTS with computational efficiency of QSS. Sensitivity of simulations to load model and the need for updating the whole model with frequency variations are also discussed. [less ▲]

in International Journal of Electrical Power & Energy Systems (1997), 19(3), 195-208

We propose an integrated scheme for transient stability assessment which in a sequence screens contingencies and scrutinizes only the selected ones. This scheme is based on a hybrid method, called SIME ... [more ▼]

We propose an integrated scheme for transient stability assessment which in a sequence screens contingencies and scrutinizes only the selected ones. This scheme is based on a hybrid method, called SIME for Single Machine Equivalent. SIME relies on a particular direct method coupled with time-domain programs so as to combine the strengths of both, namely: the flexibility with respect to power system modelling of time-domain methods; the speed and richer information of the direct method. This paper lays the foundations of SIME, devises appropriate techniques for transient stability assessment per se and for contingency screening, and finally integrates these two techniques in a fully general function, i.e. able to comply with any power system modelling and stability scenario, and to assess any type of stability limits (critical clearing times or power limits). Throughout, real-world examples illustrate the proposed techniques and highlight their performances. [less ▲]